Find a pattern to match 'a', ignoring that 'a' which lies within 'b' and 'c'

Question

Need a compound expression for

\" from\" such that \" from\" is not within parenthesis

(ignoring those which are in parenthesi

Answer 1

This may be what you want.

string s="select field1 dfd t1 (select field1 from t1)select field1 from t1";
Regex r=new Regex(@"(?<=\)|^)\bselect\b.*?\bfrom\b.*?(?=\()",RegexOptions.RightToLeft);
r.Replace(s,"HELL yeah");